The FBI had obtained a secret court order to monitor communications of Carter Page, Washington Post reported on April 11. Page was allegedly a foreign policy advisor to the Trump campaign, although Trump’s team denies his role.

Page is an oil industry consultant and founder of Global Energy Capital, a New York investment fund specializing in oil and gas industries in Central Asia and Russia, and his business deals with Russian oil companies Gazprom and Rosneft have been used to accuse the Trump campaign of dealings with Russia.

The news of the wiretap also adds evidence to the ongoing investigation into whether the Obama administration was spying on members of Trump’s campaign—possibly for political purposes. It follows news that Susan Rice, the national security adviser under former President Barack Obama, requested identities of members of then-candidate Donald Trump’s election campaign from intercepted communications.